--- a/taskcluster/ci/legacy/tasks/builds/b2g_aries_spark_debug.yml
+++ b/taskcluster/ci/legacy/tasks/builds/b2g_aries_spark_debug.yml
@@ -17,21 +17,17 @@ task:
       level-{{level}}-{{project}}-build-aries-debug-objdir-gecko: /home/worker/objdir-gecko
     env:
       TARGET: 'aries'
       DEBUG: 0
       VARIANT: userdebug
       GAIA_OPTIMIZE: '1'
       B2G_SYSTEM_APPS: '1'
       MOZHARNESS_CONFIG: b2g/taskcluster-spark.py
-    command:
-      - >
-        checkout-gecko workspace &&
-        cd ./workspace/gecko/taskcluster/scripts/phone-builder &&
-        buildbot_step 'Build' ./build-phone.sh $HOME/workspace
+    command: ["/bin/bash", "-c", "checkout-gecko workspace && cd ./workspace/gecko/taskcluster/scripts/phone-builder && buildbot_step 'Build' ./build-phone.sh $HOME/workspace"]
   extra:
     treeherderEnv:
       - production
       - staging
     treeherder:
       symbol: B
       groupSymbol: Aries
       groupName: Aries Device Image

--- a/taskcluster/ci/legacy/tasks/builds/b2g_phone_eng_base.yml
+++ b/taskcluster/ci/legacy/tasks/builds/b2g_phone_eng_base.yml
@@ -9,13 +9,9 @@ task:
       VARIANT: eng
       GAIA_OPTIMIZE: '1'
       B2G_SYSTEM_APPS: '1'
       MOZ_TELEMETRY_REPORTING: '1'
       MOZ_CRASHREPORTER_NO_REPORT: '1'
       GAIA_KEYBOARD_LAYOUTS: 'en,pt-BR,es,de,fr,pl,zh-Hans-Pinyin,zh-Hant-Zhuyin,en-Dvorak'
       B2G_UPDATE_CHANNEL: 'default'
       MOZHARNESS_CONFIG: b2g/taskcluster-phone-eng.py
-    command:
-      - >
-        checkout-gecko workspace &&
-        cd ./workspace/gecko/taskcluster/scripts/phone-builder &&
-        buildbot_step 'Build' ./build-phone.sh $HOME/workspace
+    command: ["/bin/bash", "-c", "checkout-gecko workspace && cd ./workspace/gecko/taskcluster/scripts/phone-builder && buildbot_step 'Build' ./build-phone.sh $HOME/workspace"]